(1) Field of the Invention
The present invention relates to a fuel tank mainly used for automobiles, and more particularly to the construction of the kind of fuel tank for preventing fuel from escaping to the outside air during refueling.
(2) Description of the Related Art
When refueling a vehicle driven by an internal combustion engine, such as a gasoline engine, one uncaps the fuel inlet of the fuel tank and inserts a fuel feed nozzle. However, when the fuel in the tank is low, there is a large quantity of pressurized fuel vapor in the space above the liquid surface of the fuel. When the cap is removed, the fuel vapor in the tank escapes to pollute the outside air. Also, while the liquid fuel is filled into the fuel tank, it strikes the fuel within the tank, creating bubbles which again escape to pollute the outside air.
To prevent the fuel in the fuel tank from escaping to pollute the outside air, there has been provided a recovery apparatus for fuel vapor in which the tank body is connected to the first and second canisters absorbing the fuel vapor. A change-over valve is provided adjacent to the fuel inlet of the tank body. The change-over valve communicates one of the inlets of the first and second canisters with the fuel inlet through insertion of a fuel feed nozzle. The fuel inlet is normally communicated with the first canister. The change-over valve operates and communicates the fuel inlet with the second canister when the fuel feed nozzle is inserted into the tank body (refer to Japanese Examined Utility Model Publication No. 59-10377).
In the above recovery apparatus for fuel vapor comprising the first and second canister, when the fuel volume in the tank body expands due to a temperature rise of the tank body, since both fuel vapor leading openings communicated with the first and second canister are positioned at the same level, the fuel flows as a liquid into the first canister, thus remarkably decreasing the absorbing capacity of the first canister.